Air charger systems are turbine-driven forced induction devices that increases an internal combustion engine's efficiency and power output by forcing extra air into the combustion chamber. This improvement over a naturally aspirated engine's power output is due to the fact that an intake air compressor can force more air into the combustion chamber than atmospheric pressure alone.
An air charger system can create high pressure outputs from the intake air compressor and low mass flow rates, possibly lower than what the engine needs to run, when the engine throttle body is closed rapidly which can lead to compressor surge or a back flow of air.
In order to promote optimal combustion within an engine cylinder, a manifold absolute pressure sensor is used to provide manifold pressure information to an engine controller for calculating air density, which in turn is used to determine fuel metering per cylinder needed to obtain optimal combustion. However, the manifold absolute pressure (MAP) sensor may not be capable of detecting the changes in manifold pressure that occur during compressor surge events which, if it could, would cause the engine to run off a speed density calculation of air for fuel metering. Accordingly, there is a need for a reliable means to detect compressor surge in an air charger system to enable model based air estimation for fuel metering.
Furthermore, other desirable features and characteristics of the present exemplary embodiment will become apparent from the subsequent detailed description of the embodiment and the appended claims, taken in conjunction with the accompanying drawings and this background.